There are more than seventy million infertile couples worldwide. Approximately one in every four infertile couples seek clinical treatment, where male factor accounts for about fifty percent of the infertility cases. The most important factors for male infertility include low sperm count and motility and sperm abnormality, which reduce the ability of sperm cells for oocyte fertilization. Assisted reproductive technologies (ARTs) such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and intrauterine insemination (IUI) are generally utilized in reproductive clinics to treat infertile couples. With an increasing rate of male infertility due to environmental and physiological conditions, there is an ever growing need for the use of ARTs in reproductive clinics.
There are four main factors which semen analysis tests examine: sperm concentration, sperm morphology, motility, and progressive motility. Sperm concentration tests examine the concentration of sperm in one milliliter (mL) of semen (approximately 20 million sperms/mL) though sperm concentration is not an accurate indicator of a male's ability to reproduce. Males with a low sperm count can still reproduce, and males with high sperm counts can have difficulty. This discrepancy is due to sperm motility, a crucial factor which controls how capable the sperm is of entering an oocyte. Sperm motility, the movement of sperm, must be past a certain threshold in order for the sperm to successfully be able to swim up the female vaginal tract and penetrate the oocyte's hard outer shell. Seminal quality is evaluated by determining the percentage of motile sperm cells and the relative velocity of progressively motile sperm cells in a sample. The progressive motility of a sperm is a fundamental working characteristic that controls its ability to enter into both cervical mucus and the oocyte vestments.